The study aims to define and compare the immunological characteristics (lymphocyte subpopulations, specific immunity against HIV, lymphocyte activation, inflammatory parameters) and the virological characteristics (study of viral reservoir) between 2 groups of vertically-HIV-1-infected children, between 5 and 17-year-of-age, who started cART before 6 months-of-age ("early treatment" group) or after 24 months-of-age ("late treatment" group) with an initial virologic success (HIV-1 RNA <400 copies / mL reached no later than 24 months after the start of cART), whatever the later evolution of the viremia.